Realizing 11.3 efficiency in fullerene-free polymer solar cells by device optimization

摘要

In this work, photovoltaic properties of the PBDB-T:ITIC based-NF-PSCs were fully optimized and characterized by tuning the morphology of the active layers and changing the device architecture. First, donor/acceptor(D/A) weight ratios were scanned,and then further optimization was performed by using different additives, i.e. 1,8-diiodooctane(DIO), diphenyl ether(DPE),1-chloronaphthalene(CN) and N-methyl-2-pyrrolidone(NMP), on the basis of best D/A ratio(1:1, w/w), respectively. Finally,the conventional or inverted device architectures with different buffer layers were employed to fabricate NF-PSC devices, and meanwhile, the morphology of the active layers was further optimized by controlling annealing temperature and time. As a result,a record efficiency of 11.3% was achieved, which is the highest result for NF-PSCs. It's also remarkable that the inverted NF-PSCs exhibited long-term stability, i.e. the best-performing devices maintain 83% of their initial PCEs after over 4000 h storage.